2-isothiouronium-methyl-3-carboxylic acid amido-quinoxaline-1,4-di-n-n-oxide halides as antibacterial agents and pharmaceutical compositions comprising said oxides

ABSTRACT

WHEREIN: R1 is hydrogen, lower alkyl, lower alkoxy or chlorine, R2 is hydrogen, straight or branched chain alkyl or straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino, R3 is hydrogen, straight or branched chain alkyl, straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino, or when R2 is hydrogen, cyclohexyl, or R2 and R3 together with the amide nitrogen atom form part of a 5- or 6-membered heterocyclic ring, and Hal is chlorine or bromine, in combination with a pharmaceutically acceptable inert carrier are useful for their antibacterial effect. These compositions or the active compounds can be administered subcutaneously or orally to animals and humans. 2-Isothiouronium-methyl-3-carboxylic acid-amidoquinoxaline-1,4di-N-oxide halides of the formula:

United States Patent Ley et a].

Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany Filed: Jan. 22, 1970 Appl. No.: 10,685

Related US. Application Data Division of Ser. No. 764,592, Oct. 2, 1968, Pat. No. 3,598,820.

Assignee:

[30] Foreign Application Priority Data Oct. 4, 1967 Germany ..F 53669 U.S. Cl "424/250 Int. Cl. ..A6lk 27/00 Field of Search ..424/ 250 [56] References Cited UNITED STATES PATENTS 3,157,654 11/1964 Sasse etal. ..260/250 n [5 1 Aug. 22,1972

Primary Examiner-Jerome D. Goldberg Attorney-Jacobs & Jacobs ABSTRACT 2-lsothiouronium-methyl-3-carboxylic acid- R2 0 1 T C0N N NH2 6 CH s-c -W## s w 231 W 11L wherein:

R is hydrogen, lower alkyl, lower alkoxy or chlorine,

R is hydrogen, straight or branched chain alkyl or straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino,

R is hydrogen, straight or branched chain alkyl, straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino, or when R is hydrogen, cyclohexyl, or R and R together with the amide nitrogen atom form part of a 5- or 6-membered l-lfi i s fi iise r b i iine, in combination with a pharmaceutically acceptable inert carrier are useful for their antibacterial effect.

These compositions or the active compounds can be administered subcutaneously or orally to animals and humans.

1s Claims, N0 Drawings 'doquinoxaline-l,4-di-N-oxide halides of the formu- 2-ISOTHIOURONIUM-METIIYL3-CARBOXYLIC ACID AMIDO-QUINOXALINE-l ,4-DI-N-N-OXIDE HALIDES AS ANTIBACTERIAL AGENTS AND PHARMACEUTICAL COMPOSITIONS COMPRISING SAID OXIDES This application is a divisional of our copending application Ser. No. 764,592, filed Oct. 2, 1968 now U.S. .Pat. No. 3,598,820 issued Aug. 10, 1971.

The present invention is concerned with 2-isothiouronium-methyl-B-carboxylic acid-amido-quinoxaline- 1,4-di-N-oxide halides and their production. More particularly, these compounds can be represented by the formula:

wherein:

R is hydrogen, lower alkyl, lower alkoxy or chlorine,

R is hydrogen, straight or branched chain alkyl or straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino,

R is hydrogen, straight or branched chain alkyl, straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy, monoalkylamino or dialkylamino, or when R, is hydrogen, cyclohexyl, or R, and R together with the amide nitrogen atom form part of a 5- or 6-membered.

heterocyclic ring, and

Hal is chloride or bromine.

These compounds are useful as antibacterial compounds.

The compounds of the present invention may be produced, inter alia, by reacting a 2-halomethyl-3-carboxylic acid amido-quinoxaline-l,4-di-N-oxide of the formula:

with thiourea in a suitable organic solvent at a temperature of from about 40C to about 160C.

According to the present invention, the preferred lower alkyl and lower alkoxy groups for R are those containing one to four carbon atoms. When R and R are alkyl, it is preferred that the alkyl moieties contain one to 12 carbon atoms. Particularly preferred embodiments are those wherein the alkyl groups contain from one to six carbon atoms. When the alkyl moieties of R and R are substituted by lower alkoxy, acyloxy, monoor dialkylamino moieties, it is preferred that the alkyl portions of those moieties contain from one to four carbon atoms. In the case of the dialkylamino moieties, each alkyl group is preferred to contain one to four carbon atoms. Where R and R together with the amide nitrogen atom form a part of a heterocyclic ring, such a ring may contain, besides the amide nitrogen atom, an additional nitrogen atom or an oxygen heteroatom. When R, and R form a six-membered ring containing two heteroatoms, the second heteroatom is preferably in the para position to the amide nitrogen atom and the hydrogen atom may be substituted on the additional nitrogen atom if nitrogen is the second heteroatom by lower alkyl of one to four carbon atoms which, in turn, may itself be substituted by hydroxy, methoxy or acetoxy.

If 2-chloromethyl-3-carboxylic acid methylamidoquinoxaline-l,4-di-N-oxide and thiourea are used as starting materials, the reaction of the invention can be represented by the following reaction mechanism:

(III) The 2-halomethyl-3-carboxylic acid' amido-quinoxaline-l ,4-di-N-oxides of formula H may be obtained by halogenation of 2-methyl-3-carboxylic acid amidoquinoxaline-l,4-di-N-oxides. German application No. F 53667 IVd/ 12p filed Oct. 4, 1967 and U.S. application Ser. No. 764,610 filed Oct. 2, 1968 disclose methods for producing compound II.

As examples of the 2-halomethyl-quinoxaline-l,4-di- N-oxides which can be used according to the invention as starting compounds, there are mentioned in particular: 2-chloromethyl-3-carboxylic acid methylamidoquinoxaline-l,4-di-N-oxide, 2-chloromethyl-3-carboxylic acid butylamido-quinoxaline-l,4-di-N-oxide, 2- chloromethyl-S-carboxylic acid-B-methyox yethylamido-quinoxaline-l ,4-di-N-oxide, chloromethyl-3-carboxylic acid-dimethylamidoquinoxaline- 1 ,4-di-N-oxide, 2-chloromethyl-3-carboxylic acid-B-acetoxymethylamido-quinoxalinel ,4-di-N-oxide, 2-chloromethyl-3-carboxylic acid-pyrrolidylamido-quinoxaline-1,4-di-N-oxide, 2-

bromomethyl-S-carboxylic acid-pyrrolidylamido-quinoxalinel ,4-di-N-oxide, 2-bromomethyl-3-carboxylic acid-pyrrolidylamido-quinoxalinel ,4-di-N-oxide, 2- chloromethyl-S-carboxylic acid amide-quinoxaline- 1,4-di-N-oxide, 2-chloromethyl-3-carboxylic acidmethylamido-7-methyl-quinoxalinel ,4-di-N-oxide, 2- chloromethyl-3-carboxylic acid-methylamido-7- methoxy-quinoxaline-l,4-di-N-oxide, 2-chloromethyl- 3-carboxylic acid-methylarnido-7-chloro-quinoxalinel ,4-di-N-oxide.

nun-n mu- About 1 to about 1% moles of thiourea are used per mole of 2-halomethyl-3-carboxylic acid arnido-quinoxalinel ,4-di-N-oxide.

Examples of suitable diluents are alcohols, acetonitrile, nitromethane, dimethyl formamide, dioxan, tetrahydrofuran, dimethyl sulphoxide and chlorinated hydrocarbons such as chloroform,

methylene chloride and chlorobenzene.

The reaction is carried out in the temperature range of about 40C to about 160, preferably 60C to 100C.

The new compounds of the invention are crystalline substances, which can be isolated in the usual manner.

The antibacterial activity of the compounds of the present invention has been demonstrated both in vitro and in vivo and the compounds of the present invention have, in such tests, shown utility upon both subcutaneous as well as oral administration against acute bacterial infections. The compounds are effective against a range of both gram positive and gram negative bacteria.

The general dosage ranges of the compounds of the present invention are from about 5 mg to about 300 mg and preferably from about 20 mg to about 100 mg/kg per body weight per day. It is, however, to be appreciated that in some cases it may be necessary or desirable to administer a greater or lesser amount, which amount will be dependent upon the type of infection, the severity of the condition, the body weight of the human or animal involved, the past medical history and other factors generally taken into consideration by those administering antibacterial compounds. In the case where larger amounts are administered, it is generally advisable to divide these larger dosages into several smaller doses which may be administered during the course of the day.

The compounds of the present invention may be used either as such or may be administered in combination with known pharmaceutically acceptable carriers and diluents. Suitable as administration fonns in combination with various inert carriers and diluents for the compounds of the present invention are tablets, capsules, powders, sprays, elixirs, aqueous suspensions, injectable solutions, syrups and the like. The carriers and diluents also include fillers and sterile aqueous media, as well as non-toxic organic solvents and other suitable pharmaceutical vehicles well known by those in the art. If desired, tablets, capsules or other forms used for oral administration may be provided with a sweetening additive or other suitable flavoring substance. The compounds of the present invention, which is the active ingredient in such a pharmaceutical composition, should be present in a concentration of from about 0.5 to about 90 percent by weight of the total composition.

For oral administration, tablets may also contain such known additivesas sodium citrate, calcium carbonate, di-calcium phosphate, together with various adjuvants such as starch, preferably potato starch, and the like, and binders such as polyvinylpyrrolidine, gelatin and the like, lubricants such as magnesium stearate, sodium lauryl sulphate and talc may also be used for tablet-making. For aqueous suspensions and/or elixirs which are intended for oral administration, suitable substances to improve the taste, dyestuffs, emulsifiers and/or diluents, such as water, ethanol, propylene glycol, glycerol and the like, may be added.

For solutions intended for parenteral application, the compound'of the present invention may be combined with sesame oil or arachis oil or aqueous propylene glycol or N,N-dimethyl formamide may be used, as well as sterile aqueous solutions when water soluble compounds are utilized. If necessary, such aqueous solutions can be buffered in known and customary manner and the liquid diluents should be rendered isotonic beforehand by the addition of the requisite amount of salt or glucose. Such aqueous solutions are particularly suitable for intravenous, intramuscular and intraperitoneal injections. Sterile aqueous media may be prepared in manners per se known in the art.

The following data shows the effectiveness of compounds selected as representative of the class as a whole and the number of the compounds tested corresponds to the example number. These tests demonstrate the efi'ectiveness of representative species and the genus as a whole embraces compounds having antibacterial activity already indicated.

In the animal experiments with white mice, the intraperitoneally infected animals were treated subcutaneously or orally as follows:

1. Administration in one dose, subcutaneously or orally, of 1000 mg, 500 mg, 200 mg, mg, 50 mg, 25 mg, 12.5 mg or 6.25 mg/kg 15 minutes before or 90 minutes after infection.

2. Administration in two (or three) doses of 6.25 mg, 12.5 mg, 25 mg, 50 mg or mg/kg 2 hours before and 5 hours after infection.

3. Administration in four doses of 50 mg 'or 150 mg/kg 2 hours before infection, shortly before infection, 3 hours, 5 hours and/or 21 hours and 29 hours after infection.

The bacteria used for infections were E. coli, Klebsiella, Staphylococcus aureus, Diplococcus pneumoniae or Streptoccus pyogenes, Proteus mirabilic and Pseudomonas aeruginosa. The ED of the most efiective compounds e.g., 1, 3 and 4) against E. coli C or Staph. aureus 133 lies, in the case of administration in one dose, orally or subcutaneously, between 25 mg/kg and 100 mg/kg. I

The DL lies in the dosage range of about 400 mg/kg to about 1500 mg/kg after oral administration in one dose to mice. The substances are thus relatively nontoxic sinoe the relatively less well tolerated ones are distinguished by higher effectiveness and are, therefore, applied only in low dosage. Also in the case of treatment of rats with 60 mg/kg orally twice daily over 17 days, the substances were well tolerated. In the case of acute ascending infections of the urinary tract of the rat (pyclonephritis), dosages of 2 X 15 mg/kg daily, is. 15 mg/kg twice a day, over 7-10 days were applied with success and were tolerated well. In vitro, the substances act bacteriostatically and bactericidally.

The new compounds are also efi'ective against Mycoplasma infections in the in vitro test, amounts of about 5 to about 50 7 per ml being used.

1.ANIMAL EXPERIMENTS WITH THE WHITE MOUSE Pertgt surviving animals 24 hours after infection. 7

. h a u. Anya 5 6 VITRO EXPERIMENTS 29.5 g (0.1 mole) 2-chloromethyl-3-carboxylic acid- Mlnlmum inhibition concentration in gJml. nutrient medium l id inoxaline-1,4-di-N-oxide are Example 1 2 3 4 5 6 suspended in 200 ml acetonitrile, 8 g (0.1 mole) thiOU- g H m 100 100 100 100 5 tea a tg g i lg bill effectedage gee-w 2% 133 132 at: 388 2122???? a S e Klebsiella M 1o 100 100 100 100 pr separates m crystallme for-m Heatlng g gl 1 m l. 19 3 1 s continued for a further 2 hours, with stirring; cool ng is eifected, followed by suction filtration. After washing The new 2-halomethyl-3-oarboxylic acid amidoout with hot methanol, 28.5 g 77 percent of the qumoxalme-1,4-d1-N-oxides also ShOW (same general 10 theory) of the compound of the above f m are b.

dosage latitude as stated above) effectiveness against amoebae and flagellates (E. histolytica, Trichomonas tamed m analyucal gmfie form as R l crystals vaginalis, Lamblia muris) in in vitro as well as in vivo whichmelt 2l C,w1 hde mp s1 1 ntests 011 animals mice, rats, golden hamsters) The other compounds, that is, those whose formulas M.P., 0. Example No. Formula d=decornp. Appearance 1 O 210 Pale yellow T crystals. /N\ CO-NH-CaH \N/ cH,s l o NH 01- 1V 2 0 238(d) Do.

r III 00 NH 2 G /NH \N/ c112-s0 l o NHL-l 01- (v) 3 (T) 189((1) Do.

/N\ CONHCHa 9 /NH2 \N/ CH2-SC/ l 0 NHL or v1 4 r- 0 CH 223 0) Do.

T co-NH-o N\ CH3 0 /NH2 f CH -SC o NH2 01- v11 5 F g) 214((1) DO.

/N\ o0-N11 o4m 9 N H2 \III/ \CH2-SC 0 NH; 01- (VIII) /N\ CO-NHC(CH:1)a

9 NH; \III/ CHzS-C o NH2 01- (IX) The preparation of the compounds is illustrated by are set forth as Examples 2 through 6 are prepared in a similar manner by reacting, respectively:

the following examples:

0 2-chloromethyl-3-carboxylic acid-amide-quinoxaline- X A MP 1 ,4-diN-oxide with thiourea; LE 1 2-chloromethyl-3-carboxylic acid-methylamido'quin- C C H oxaline- 1 ,4-di-N-oxide with thiourea; a 7 2-chloromethyl-3-carboxylic acid-isopropylamido- NH2 65 quinoxaline-l ,4-di-N-oxide with thiourea;

2-chloromethyl-3-carboxylic acid-butylamido- 1 NH quinoxaline-1,4-di-N-oxide with thiourea; 0 I (IV) 2-chloromethyl-3-carboxylic acid-tert.-bu-

\N/ claws-0 -methylamido-quinoxaline-di-N-oxide-( l .4)

tylamido-quinoxaline-l ,4-di-N-oxide with thioutea.

The starting material, 2-chloromethyl-3-carboxylic acid-methylamido-quinoxaline-l,4-di-N-oxide, set forth above may be obtained as described in German application No. F 53667 IVd/l2 p filed Oct. 4, 1967 and US. application Ser. No. 764,610, filed Oct. 2, 1968.

This procedure is generally asfollows:

A. 233 g (1 mole) 2-methyl-3-carboxylic acid are suspended in 700 ml chloroform and heated to the boil. Into the boiling mixture there are introduced, within 3 hours, with stirring, 90 g (2.5 gram atoms) of chlorine. First the starting material dissolves, then the reaction product separates in crystalline form. Stirring is continued for 30 minutes at boiling temperature; air is then blown into the reaction mixture for 30 minutes in order to remove the HCl which is formed, and this is followed by cooling and suction filtration. After recrystallization from ethanol/dioxan, 181 g (=68 percent of the theory) of 2-chloromethyl-3-carboxylic acid methylamido-quinoxaline-di-N-oxide-(1.4) are obtained as yellow crystals which melt at 195C-l 96C.

Analysis: C H ClN,O, (molecular weight 267.5) Calc: CI: 13.3% Found: CI: 13.0

B. The same substance was obtained by chlorination in glacial acetic acid at 85C90C. For working up, the reaction solution obtained is poured into water. A yellow oil separates, which crystallizes when rubbed with methanol. The substance shows no depression of melting point with that described under A.

In manner analogous with that described in the above Example, the other 2-halomethyl-3-carboxylic acid amido-quinoxaline-l,4-di-N-oxides used for the reaction according to the invention can also be obtained.

In addition to the new compounds and processes disclosed herein, the present invention also includes pharmaceutical compositions containing at least one compound of the present invention in combination or admixture with a solid or liquid diluent or carrier, as well as methods of treating bacterial infections. The present invention also includes unit dosage forms comprising at least one compound of the present invention either alone or in admixture or combination with a solid or liquid diluent or carrier. The compound may be suitably enveloped by a protective covering containing the compound itself and, if used, a diluent or carrier.

The term medicament in dosage unit form as used in the present specification means a medicament as defined above in the form of discrete portions each Containing a unit dose, or a multiple or sub-multiple of a unit dose of the active compound or compounds. Such portions may, for example, be in monolithic coherent form, such as tablets, suppositories, pills or dragees; in wrapped or concealed form, such as wrapped powders, cachets, sachets, or capsules; in ampoules, either free was a sterile solution suitable for parenteral injection; or in any other form known to the art.

What is claimed is:

1. A pharmaceutical composition for the treatment of bacterial infections which comprises an antibacterially effective amount of a compound of the formula:

(T) R: N 0 *N 10 wherein R is hydrogen, lower alkyl, lower alkoxy or chlorine,

R is hydrogen, straight or branched chain alkyl of one to 12 carbon atoms or straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy of one to four carbon atoms, monoalkylarnino or dialkylamino of one to four carbon atoms,

R is hydrogen, straight or branched chain alkyl of one to 12 carbon atoms, straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy of one to four carbon atoms, monoalkylarnino or dialkylamino of one to four carbon atoms, or when R is hydrogen, cyclohexyl, or R and R together with the amide nitrogen atom form part of a fiveor six-membered nitrogen containing heterocyclic ring, and

Hal is chlorine or bromine,

in combination with a pharmaceutically acceptable non-toxic inert diluent or carrier.

2. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

3. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

\ y l O T 00 NH:

4. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

5. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

6. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

7. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:

NH2 CHz-SC 8. A pharmaceutical composition according to claim 1 in oral administration form.

9. A pharmaceutical composition according to claim 1 in parenteral administration form.

10. A method of treating bacterial infections in humans and animals which comprises administering to a human or an animal an antibacterially effective amount of a compound of the formula:

wherein R is hydrogen, lower alkyl, lower alkoxy or chlorine,

R is hydrogen, straight or branched chain alkyl of one to 12 carbon atoms or straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy of one to four carbon atoms, monoalkylamino or dialkylamino of one to four carbon atoms,

R, is hydrogen, straight or branched chain alkyl of one to 12 carbon atoms, straight or branched chain alkyl substituted by hydroxy, lower alkoxy, acyloxy of one to four carbon atoms, monoalkylamino or dialkylamino of one to four carbon atoms, or when R is hydrogen, cyclohexyl, or R and R together with the amide nitrogen atom form part of a fiveor six-membered nitrogen containing heterocyclic ring, and

Hal is chlorine or bromine,

until amelioration of the condition occurs.

11. A method of treatment according to claim 10 wherein from 5 mg/kg to 300 mg/kg is administered.

12. A method of treatment according to claim 10 wherein the compound is of the formula:

13. A method of treatment according to claim 10 wherein the compound is of the formula:

14. A method of treatment according to claim 10 wherein the compound is of the formula:

15. A method of treatment according to claim 10 wherein the compound is of the formula:

16. A method of treatment according to claim 10 wherein the compound is of the formula:

17. A method of treatment according to claim 10 wherein the compound is of the formula:

m1 nzn nos: 

2. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 3. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 4. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 5. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 6. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 7. A pharmaceutical composition according to claim 1 wherein the compound is of the formula:
 8. A pharmaceutical composition according to claim 1 in oral administration form.
 9. A pharmaceutical composition according to claim 1 in parenteral administration form.
 10. A method of treating bacterial infections in humans and animals which comprises administering to a human or an animal an antibacterially effective amount of a compound of the formula:
 11. A method of treatment according to claim 10 wherein from 5 mg/kg to 300 mg/kg is administered.
 12. A method of treatment according to claim 10 wherein the compound is of the formula:
 13. A method of treatment according to claim 10 wherein the compound is of the formula:
 14. A method of treatment according to claim 10 wherein the compound is of the formula:
 15. A method of treatment according to claim 10 wherein the compound is of the formula:
 16. A method of treatment according to claim 10 wherein the compound is of the formula:
 17. A method of treatment according to claim 10 wherein the compound is of the formula:
 18. A method of treatment according to claim 10 wherein the administration is oral.
 19. A method of treatment according to claim 10 wherein the administration is parenteral. 